Rheostat.



PATENTED APR. 28, 1908.

E. L. MAHON.

RHEOSTAT.

APPLICATION FILED v*JUNE 6, 1907.

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EDWARD L. MAHON, OF BELLAIRE, OHIO.

RHEOSTAT.

Specification of Letters Patent.

Patented April 28, 1908.

Application led June 6, 1,907. Serial No. 377,668.

To all 'whom it may concern:

Be it known that l, EDWARD L. M'AnoN, a citizenof the United States, residing at Bellaire, in the county of Bellnontand State of' Ohio, have invented certain new and useful Improvements in Rheostats; and l do hereby declare the following'to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertaiiis to make and use the same. j

My invention relates te certain new and useful improvements in rheostats and particularly to that type in which wateris einployed as the resistance medium.. lIn the .type referred to the conductors are located within an open water receptacle and the resistance offered to the current is controlled by the adjusted relation of the conductor p ates.

My invention has for its object to provide a Water rheostat in which the conductors are located. adjustably within a water compartment in such manner that the resistance f body is under compression in contradistinction to being located within an open vessel or compartment. I

My invention has also for one of its objects to control the resistance by simple and readily operated means and it has also for one of its objects simplicity and economy of construction.

With these ends in view my invention consists in the construction and arrangement hereinafterand in detail ex ilained.

In order that those skilled inthe art to which my invention appertains may know yhow to make and use my improved rheostat and fully appreciate all of its advantages I will proceed to describe the same referring by numerals to the accompanying drawing i in which- 1, is a plain cylinder preferably of c'ast iron although it may be made of any other suitable material and formed wlth external i screw threads as shown in Fig. 1, or internal threads as shown in Fi 2. When formed as shown in Fig. 1, meta bands 2, internally threaded are secured upon the external threads on the cylinder and extend sufficiently beyond the ends of the cylinder to receive heads 3, and 4, com )osed preferably of vulcanite iiber, althougli any other suitable insulating material may be employed. The head 3, is of sufficient thickness to constitute a rigid support for a centrally arranged stuifing box 5, which is formed with a flange G, bearing against the inner surface of the liead 3, and secured in position by a nut 7. The head 4, which is secured in the opposite end of the cylinder is provided upon its inner surface with a metal conductor disk 8, attached thereto by rivets'Q, or in any other suitable manner. The diameter of lthe conductor plate is somewhat less than the vulcanite head as shown to provide a seat for a ring insulator 10, located between the end of the cylinder and the head 4, to constitute perfect insulation between the i-conductor 8, and the cylinder, and 11, is a similar insulation between the opposite end of the cylinder and the head 3. A binding post 12, passing through the head 4, is secured to the conductor disk 8, and is adapted in an obvious manner for connection with an external circuit, j

13, is an overflow or discharge pipe cornmunicating with the up er surface of the cylinder, and 14, is an 1n et pipe secured in the head 3, at its lower ed e, and adapted to connect with a water supp y and is 'provided with a controllin valve 15. The relation of the inlet and out et pipes 14, and 13, issuch that the cylinder may be at all times kept with a full sup ly oi Water.

16, is a con uctor disk similar to the disk 8, and is secured to the end of a metal stem 17, which passes through the stufiing`box 5, and is provided with a binding post 18, and a suitable operating handle 19. A longitudinally adjustable stop 20, is secured upon the stern 17 by a set screw 21, the purpose of which stop'is to limit the approach of the disk 16, toward the stationary disk 8, to any predetermined locality; The interior surface 4of the cylinder is enameled as indicated at 22, to constitute a satisfactory insulation, and said cylinder may likewise be enameled on its outer surface.

In the modification shown at Fig. 2, in which the vulcanite iib'er heads are secured within the interior threads of the cylinder the insulating rings 10, are not required. As hereinbeforef` stated the cylinder may be made of glass, pottery or any other material having insulating properties, or of any suitable materialA capable of being insulated, though I prefer'to make it of iron on account l of its strength and stability.

The stem 17, may be provldedwith a suitable scale 23, which according to its relation to theextremity of the -stuiingbox will in. dicate any desired resistance obtained by the distance apart of the `conductor disks 8, and 16.

From the construction shown and described it will'be readily. seen that when the cylinder is supplied with water from any suitable source through the inlet pipe 14, 1t is kept full and under ressure and that the conductor disks 8, andp 16, are always completely submerged, and being perfectly insulated from the cylinder` the body of water between the disks constitutes the resistance which is greater or less according to the distance apart of said disks, thus securing absolute an accurate control of thecurrent, and it will' be obvious that the' disks may be separated to-such a distance that the excesslve resistance will constitute a complete cutout,

thus rendering independent cut out devices unnecessary. l

The water supply being controlled by the valve 15 and being under constant pressure,

I have found to be of great advanta e as I have determined from practical tests t at by applying pressure and feedin the water rapidly to the containing vessel am enabled to controlla high voltage and at the saine time prevent t e rheostat from heating to any great extent, while with the use of an open vessel. and without pressure, a similar twenty minutes.

Having described the construction,l operation and advantages of my. improved rheostat what I claimas newv and desirel to secure by Letters Patent 'is-F under pressure; an insulated stationaryconductor plate; a `movable conductor. plate;

and means for adjustin ductor plate substantia set forth. 4 v l 2. In a rheostatprovided with a stationary and an adjustable conductor plate,

pressure between the conductor plates, substantially .as and for the purpose set forth.

3. In a rheostat such as described and embodying stationary and adjustable conductor plates, a reciprocatin stem for adsto located upon said stem, substantially as ereinbefore set forth.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses. v

. EDWARD L. MAHON.

Witnesses: D. G. STUART,

JNO, J. HARRowER.

voltage will cause the water to boil in about means for supplying and dischar water,

the mova le cony as hereinbefore` means for interposing a body of water under' justing one of said plates, an an adjustable 1. In a rheostat adapted to contain water 

